I'm thinking of doing the '5 Wizards for $35' deal from Gateway's site. I figure that'll give me a good mix of weights/plastics to learn which I like better/worse for putting/driving/approaching.

sleepy

do it. it's the best deal around! wizards are putters you can throw off the tee, approach with, and putt with... they fly sweet! the plastic is quite stiff for the soft, medium, and hard wizards, so they feel a little funny at first... but they're such a solid disc it's worth getting to know them. they're great for practicing throwing form with putters... which is nice for driving and approaching when you're on the course. they work great for putting in pretty strong winds, too... which in my book is a HUGE plus for a putter; being able to throw it in all wind conditions.

A bag is going to have to be my next purchase, but it seems like everytime I buy a disc I retire another one, so I keep hanging around the 3-4 mark. Sometimes I would like to have my DX Aviar instead of my Elite-Z Magnent though, and now I don't carry both.
I love my Magnent, but on my home course where every basket is on a 30 degree slope, the Aviar seemed not to run away on missed putts/ approaches.

I'm really having problems learning the X-step though, I can get the footwork right, but not the bent elbow, or I can get the bent elbow and not the footwork.

I'd like to say again though how helpful this site has been no matter what I was trying to learn.

sounds like your x-step is probably forcing your upper body around too early when you are trying for the bent elbow. it is pretty common, especially when learning something that is much harder to time.

my advice is to make sure that your pivot foot has hit the ground before your upper body starts moving forward.